The present invention is directed to a micromachined pump apparatus having a diaphragm adjacent an internal closed space for the closure thereof which operates in such a manner that whenever the volume of the internal closed space is increased, the diaphragm is deformed or expanded toward a passage, thereby forcing an object fluid to move in the passage.
Miniature pumps, hereinafter referred to as micropumps, can be constructed using fabrication techniques adapted from those applied to integrated circuits. Such fabrication techniques are often referred to as micromachining.
Micromachined pumps or micropumps are disclosed for example in Japanese Patent Laid-open Print No. Hei. 10(1998)-159811 and Japanese Patent Laid-open Print No. Hei. 7(1995)-139471.
In the former, the increase of pressure in the closed space which causes the expansion of the diaphragm is made in such a manner that a light beam is applied to a light/heat converting substance accommodated in the closed space and the resultant heat generation causes the operating fluid in the closed space to expand. However, the light application requires an optical fiber which is not very efficient in transmitting light and an optical transmission mechanism per se is expensive.
In the latter, the diaphragm is expanded by supplying air into the closed space. However, a large pressure loss occurs between a pressure source and the micropump, thereby requiring a relatively large scaled pressure source for effective expansion of the diaphragm.
Accordingly, a need exists for a micromachined pump apparatus without the foregoing drawbacks.